Curved strips of this kind are usable, especially but not exclusively, for manufacturing high-strength lightweight tubing by helically wrapping shaped curved strips. It has already been proposed, for example, in French Patent 2,312,356 to make a strip of reinforced plastic by packing with a mixture of high-strength filaments and crosslinkable plastic, a molding element in the form of a groove wrapped around a mandrel, with the strip being extracted from this molding element following at least partial crosslinking, and with the crosslinking possibly resulting from heat treatment.
However, during the manufacture of such shaped curved strips, the length of the strips produced by machine is rapidly limited by the fact that the number of turns of the molding element on the mandrel is limited, and by the crosslinking time to which the strips are subjected while in the molding element. Thus, the number of turns of the molding element, most of which is located inside the crosslinking means, is limited mainly by the problems involved in advancing the molding element on the mandrel, with the difficulties increasing with the number of turns.